An aircraft cabin sidewall is typically provided with decompression vent openings. Each of these vent openings may be covered by a grille that conceals the opening from view. The grille permits air to flow from the cabin outward through the opening in a decompression condition, and also attenuates noise generated by an ordinary return air flow through the grille. The air flow and noise control features of the grille may be provided by an arrangement of louvers on the grille.